Model T info...

[Ryan_77uk]

A few things...

Where can I find a printable copy of the original Model T manual, if their is one?

Has anyone got a schmatic of the Model T that is good quality and small enough to print?

Model T's are 150w RMS, so they must put out around 200 peak, is that right?

Thanks...

[Ryan_77uk]

also... is the original Model T Class A or Class A/B? Thanks...

[Isaac]

AB.

There are very few Class A amps, and they tend to be small. All Sunn amps have been Class AB from the start.

[iammr2]

A few things...

...

Model T's are 150w RMS, so they must put out around 200 peak, is that right?

Thanks...

Hi Ryan,

The 6550 tubes only rate 26-27 watts each, so on an original Model T it's probably more conservative to rate it as a 100 watt amp.  That's using factory settings on bias adjustments.  Mine at it's current settings puts out 96 watts of clean power.  It has Svets in it and the original output caps but I'm thinking about getting it recapped.  I don't think that will increase the wattage though.  Don't have any experience with the second generation (red knobs/logo with mid switch).

[Ryan_77uk]

I just got mine back from a service and it sounds awesome. I also have 6550's in.

[Anonymous]

iammr2...

A push-pull power amp operating in Class AB can easily put out twice the plate dissapation rating of it's tubes.  Only in Class A is the tube limited to the plate dissapation.

150w RMS from a quartet of 6550 is loafing along.

[iammr2]

Hi guest,

Not to be argumentative, but if that's the case, why didn't they design it to produce the full 200 watts (or 300 for those that think it's rated 150 watts)?  200 watts at that time would have made that amp one of the hottest amps in the business.  Are you talking about peak power while I'm speaking in terms of continuous signal RMS?

[JoeArthur]

Iammr2 - That's an interesting question, but only the original designers can answer that one.  But it is fun to speculate and I have some ideas to toss around.

Tone - obtaining maximum power from a particular circuit design doesn't always result in the best tone.  One example that proves this out are the 135watt Fenders (e.g. twin reverb, 4-6L6 outputs).  None of these are sought after for their tone, while the 85 watt blackface twin reverb with 4-6L6 outputs most definitely is a tone monster.

Reliability - what good is maximum power if it requires retubing after each gig or quits in the middle of one?  The closer to maximum operating limits a tube is run, the shorter it's lifespan.

Economy - meaning things like parts availability for manufacturing.  It's much cheaper to use parts you either have on hand or know you will have a good supply stream for - ya don't wanna do custom everything because it costs more.  

Higher voltage power transformers and output transformers would be necessary to obtain more output.  Higher voltage also puts more stress on other components which would have to be upgraded to maintain reliability - you wouldn't want an amp with more weak links than just the tubes which are "user serviceable".  All of this would cost more.

Hmm... I'm not a big fan of Marshalls... but wasn't there a "Marshall Major" that was rated 200watts RMS?  I think maybe Ritchie Blackmore used one in Deep Purple.  Despite it's power output it wasn't really all that popular.

Concerning RMS vs Peak power ratings.  RMS is not all that standardized, as power output measurements do need to specify a certain distortion figure.  Most amp manufactures usually use a 5% distortion level, but that is not always the case.  

Peak power ratings are even less standardized and are probably determined by the marketing department.

[iammr2]

Hey Joe (forgive me but I couldn't resist).  Can't argue with your logic about tone, economy, and reliability.  That may have been the case on the earlier stuff.  I do think that after the company was sold those traits might have been replaced with more emphasis on profitability and the bottom line.  Therefore they'd up the wattage ( ah, the volume wars ) and risk the tone.  They had to remain competitive with Marshall for guitar and SVT's and Acoustic's for bass.  In other words, they'd sacrifice tone for more wattage while economy and reliability remained the same.  Looks like the SVT won, as there is no more Sunn))) or Acoustic any more.  Just ramblin'.

[JoeArthur]

Perhaps you're right.  A company will do strange things all in the name of the bottom line that backfires.  As far as the Model T, certainly the second generation gave up guitar tone (for something, it wasn't power, I still haven't figured that one out) and it was eventually dropped by guitar players.

Bass players are a weird lot (I play bass also so I can say that).  The SVT has so much garbage in the power amp circuit to cut the high end to maintain stability and prevent oscillation, it amazes me that even bass players use them.

It's interesting how Fender tried to cash in on the Sunn name without success.

[Anonymous]

HEY JOE

Aren't you the guy that had that site about second generation model t modifications?  

If so where is it?  I did the snip of the master volume wire and had the cap wired up to the middle control when the site just disappeared.  Those two easy mods really helped out the amp and I hadn't finished understanding the others.  

Andy Webb

[JoeArthur]

Dang it!!  Yes Andy. I'm caught.

The site disappeared because I gave up on Cox that took over for what used to be "@home".  It's a long boring story of lack of customer service that no one really wants to hear.

And I realize I didn't respond to your email.  I don't expect this to be considered as an excuse, but I just haven't had the time.  I have responded to some as time would allow.  

I am working on putting up the information again, using my AOL space.  However, for those on AOL you will know what I mean - it is not exactly clear how much "webpage" space you have, and the doco mentions 2mb and 20mb as if they were the same thing. (arrrgh).

Soon, real soon (and the check is in the mail as the saying goes). I will post the URL here when I can.

Thank you for your patience and understanding.

Joe

[Tman]

ooooh, this is good to hear. I have a 1974 T, and a Fender T and was wondering what mods could be done on the Fender. I like them both and can use them both but the Fender needs some tweakage\thickening. I plan on running both amps in a dual setup - 1974 dry, Fender wet, or something like that.

I imagine the webspace at AOL is 2mb. 20mb would be huge, unless you're buying bulk space. Free space is likey 2mb.


HuberT

[Ryan_77uk]

By what means can a Model T be dated? The pots?